Portuguese Man of War, Physalia physalis

Reproduction

Physalia
reproduction takes place mostly in the fall.Physalia are dioecious, meaning that each “individual” is either
male or female.The polyps
responsible for reproduction are the gonozooids, which are comprised of
gonophores; sacs containing either ovaries or testes. Fertilization occurs
externally when the men of war shed their gametes into the open ocean; sperm
from one colony fuses with the eggs of another colony.It is unknown what causes this spawning cycle to begin.However, the release of gametes may be triggered by a chemical response
due to the presence of men of war in large quantities in a single locality.This critical density is probably needed for successful fertilization.Physalia physalis also
reproduces a sexually by means of budding or mitotic division.